Process of manufacturing hydrogen or gases rich in hydrogen



Sept 30, 192% J. H. WEST ET AL PROCESS OF MANUFACTURING H'L'D'CGEN OR GASES RICH IN HYDROGEN Filed Jan. l0. 1923 Patented @cpt 30, i024..

NETE@ STT 11,510,442 PATENT @FFME JOHN HENRY `WEST, OE BAYSWATEE, LONDON, ARTHUR JAQUES, or WATERLOO, AND CORNELIUS BRYITTIFEE TULLY, or NEwARE-oN-TEENT, ENGLAND.

' PROCESS OF MANUFACTURING HYDROGEN OR GASES RICH IN EYDROGEN.

Application led January 10, 1923. Serial No. 611,733.

T o all whom t may com/eraf Be it known that we, JOHN HENRY WEST, ARTHUR JAQUES, and CORNELIUS BRITTIFFE TULLY, all subjects of the King of Great Britain, residing, respectively, at Bayswater, in the county of London, England, Waterloo, in the county of Lancaster, England:4 and Newark-on-Trent, in the county of Nottingham, England, have inventedv certain new and useful Processes of Manufacturing Hydrogen or Gases Rich in Hydrogen, of which the following is a speciicav tion.

This invention relates to the manufacture of hydrogen or gases rich in hydrogen by the complete gasification offuels containing a relatively high percentage of volatile constituents, such for example as bituminous coal, as opposed to fuels of the type of anthracite and coke which contain a relatively low percentage of volatile matter.

Amongst the various methods that have been proposed for obtaining hydrogen or gases containing a relatively high proportion of hydrogen from fuel or from fuel and steam are thelfollowingzf (a) Ordinary coal gas, obtained by the carbonization of coal in closed retorts, contains part of the hydrogen originally present in the coal, this being no doubt set free by 'the partial cracking of the hydrocarbons, and methods are known for setting free pracvtically the whole of the hydrogen present in the coal by cracking the hydrocarbons completely by passing them through a bed of incandescent coke or highly heated refractory material. Many coals contain about 5 per cent by weight of hydrogen, which corresponds-to about 21,000 cubic feetl of hydrogen at 15 C. and atmospheric -pressure per ton of coal.

(b) The `production of a mixture of roughly equal volumes of hydrogen and carbon monoxide, known as blue water gas, by acting with steam on the incandescent coke resulting from the carbonization` of foal in retorts or coke` ovens is also well known. In this case part 'of the coke has to be burntiin order to raise the remainder to a high temperature and to provide the large amount of heat absorbed in the water gas reaction C-}H,O=CO+H,`. One ton of average good coal will yield about 1500 lbs. of coke, of Awhich about 500 lbs. will (d) Various methods for carrying out a reaction between the carbon monoxide in the gas obtained by methods (a) and (b) principally the latter method (o), and steam, according to the equation CO+H2O:CO,-{-H catalysts often'being used to increase the speed of the reaction. In this way a further quantity of hydrogen can be produced, which, supposing the reaction could be carried to'completion, would amount to about 28,000 cubic feet per ton of original coal.

Further in Order to avoid the loss of heat and fuel incurredv in cases where coal is eov carbonized in one vessel and the resulting coke is withdrawn into the air and quenched by water, various methods have been proposed for the complete gasification of coal in one vessel or apparatus, that is to say, by carbonizing the coal in the upper part of the apparatus, and allowing the resulting coke vto fall or pass directly, while still hot, into the lower part of the apparatus where the water gas reaction takes .fplace on steam being blown in.

The present invention has for its object the production of hydrogen by the aid of a. complete or self-contained apparatus in one or other of the component parts of which there are utilized the various methods of obtaining hydrogen referred to in (a), (b), (c) and (d) above, and, as will be seen from what follows hereinafter, it comprises a particular method for the complete gasiication of the fuel employed in the process so as to produce a mixture of gases consisting mainly of hydrogen and carbon monoxide and some carbon dioxide and the conversion of the carbon monoxide in the gases resulting from, the complete gasication by the aid of steam and in the Vpresence 0f a Catalyst t0 Carbon dioxide and hydrogen.

It is to be understood that the term oo mplete gasification, as used in connection with the process of the` present invent-1011, is employed as designating a process 1n which the resultant products consist practically wholly of what are usually termed permanent (i. e. non-condensable) gases and ash alone, the tarry vapors and hydrocarbons produced during the carbonization of the coal becoming decomposed, as completeas possible, into hydrogen and carbon' (sivhich latter becomes available for the water gas reaction as well as the so-called fixed carbon of the coal) as hereinafter described.

According to a process for the production of a gas rich in hydrogen recently invented by one of the present applicants and embodied in application Serial No. 591,824, led October 2, 1922, fuel such as bituminous coal, containing a relatively large percentage of volatile constituents, as compared with fuel, such as anthracite or coke, which contains only a relatively low percentage of volatile hydrocarbons, is distilled in an externally heated jacketed retort arranged abovea lowerfuel chamber into which the fuel which has been carbonized in the retort descends and wherein, after being raised to a state of incandescence, by blowing it with air, it is converted, by injection of steam, into water gas which is allowed to mix with the gases produced by .the distillation of the coal, the hydrocarbons whether condensable or non-condensable present in the latter gases being cracked or split up as completely as possible during the passage of the said gases through part or the whole, as the case may be, of the fuel bed in the lower fuel chamber and through the jacket surrounding the retort, so that a. mixture of water gas and permanent gases is thus obtained. This mixture of gases consists largely of hydrogen and carbon monoxide together with some carbon dioxide.

Throughout the present specification and claims the expression intermittent mixed gas generato-r isused to designate gas generating apparatus constructed and operating in the manner just described.

According to the present invention` the process for the production of hydrogen or gases rich vin hydrogen consists in effecting the complete gasification of coal by means of an intermittent mixed gas generator, taking ofi' from the generator the hot mixture of gases resulting from the complete gasification` which consist largely of hydrogen, and carbon monoxide with some carbon dioxide, and subjecting the said mixture of gases Whilst still' in the heated condition and lwithout any intermediate cooling to treatment with steam in the presence of a catalyst in a carbon monoxide converter so as to effect replacement of the carbon monoxide in the gases by carbon dioxide and hydrogen.

On removal ofy the carbon dioxide from the gases after their treatment in the carbon monoxide converter, the remaining gas consists to a large extent of hydrogen, the actual proportion of hydrogen depending however on the extent to which the reaction of carbon monoxide to carbon dioxide in the converter is allowed to proceed, this extent being determined by considerat-ions which will hereinafter be referred to.

In order that the invention may be clearly understood and readily carried into effect the same will now be described more fully with reference to the accompanying drawings. in which:-

Figure l shows the intermittent mixed gas generator in vertical section with the carbon monoxide converter and the connections thereto diagrammatically indicated. and

Figures 2, 3 and 4l are horizontal sections on the lines iwi, 2 2, and 3-3 respectively7 ofthe generator shown in Figure l.

The intermittent mixed gas generator comprises an upper retort portion A. which may be of truncated conical shape into which the coal is fed at the top through a suitable valve of cone or sliding type, and a lower chamber C constituting the gas prodtcer. Surrounding the retort A and serving to heat it is a jacket B charged with chequerwork and surmounted by an equalizing chamber D. the jacket being heated to the desired high temperature by passing through it the producer gas obtained b v blowing air through the mass of carbonized fuel in the lower chamber together with a secondary supply of air to insure complete combustion of any combustible gases within the jacket as hereinafter described. The gases of combustion or blow gases pass through the equalizing chamber D at the top of the chequer-work, after which they are discharged into the atmosphere after their sensible heat has been removed as effectively as possible by utilizing it for example for raising part of the steam required or for preheating the air for blowing the producer. Alternatively part or all of the blow gases may be used for maintaining the carbon monoxide converter K at thedesired temperature as A.hereinafter described. The coal passes slowly down through the retort. whilst being heated by the hot gases travelling up through the jacket B of the apparatus. and is thereby carbonized` the resulting carbonizcd coal falling direct into the prduc-er C. After the carbouized fuel in theproducer (l has been raised to a. high state of incandescence by blowing air through it, (the air inlet at the base of the producer chamber beingr indicated at E), the air supply is cut ofi and steam forced into the incandescent fuel, the water gas` Anostrils and into and through the jacket B.

a mixture of gases consisting largely of hydrogen and carbon monoxide, together with some carbon dioxide, being thus obtained. The gas evolved from the coal dur# ing its distillation on its way to the nostrils F has to pass downwards through the high temperature zone at the lower part of the retort and the top of the incandescent fuel in the lower fuel chamber, whereby tar and volatile hydrocarbons contained iu the said gas are partly cracked or split up, and the resultingl gases together with the water gas produced during the make pass together through the nostrils F and into the jacket B. Volatile hydrocarbons'which have escaped cracking or splitting up in the high temperature Zone referred to will be cracked or split up in the jacket B of the retort by Contact with the previously heated chequerwork therein. On leaving the upper part of the chequer-work the gases pass through the equalizing chamber D and thence through the outlet R and pipes S,- T and U to the carbon monoxide converter K as hereinafter described. A secondary supply of air is admitted to the lower end of the jacket B ofthe retort through the inlet G, whence it passes round the annular duct L and through the ports M to a combustion chamber l-l below the jacket B and in communication therewith and with the nostrils F, so as to insure complete combustion within the jacket or combustion chamber of any conibustible gas contained in the producer gas generated during the blow therehvY en ahling the heat result-ing from such combustion to be utilized in raising the temperature ofthe jacket or combustion chamber and jacket and thereby assisting in the cracking or splitting up of hydrocarbons passing into the jacket or combustion chamber and jacket from the retort. To prevent deposition of carbon in the jacket or combustion chamber and jacket by cracking or splitting up of hydrocarbons therein. steam may be admitted thereto during the make to form water gas by interaction with the liberated carbon. ln order to equalize the heating of the bed of fuel in the lower chamber C of the intermittent mixed gas generator' andv gases containing the volatile hydrocarbons issuing from the retort pass downwards with the steam tl'irough. the entire bed of incandescent fuel in the lower fuel chamber and are therein cracked or split up, the resulting mixed gases being led away from the space beneath the grate through the outlet J and pipes J1, J, T and U to the carbon monoxide converter K. Suitable pipe counections with valves are provided to enable this action to be effected. If desired a cycle of working may consist of a blow period followed by a period of steaming upwards only, or of alternate steaming upwards and downwards, and the working may consist in any convenient sequence of such cycles.

In the working of such an intermittent .mixed gas generator the heat of the blow gases. leaving the generator may advantageously be used for generating the steam or some of it required in carrying out the process, or for preheating the air used during the blow period, or for maintaining the carbon monoxide converter at the desired temperature or partly for each of these purposes. The heating of the coal in the retort may also be effected partly by introducing a regulated quantity of air into the retort itself so as to cause combustion of part of the coal therein. also to increase the percentage of hydrogen in the mixed gas eventually leaving the intermittent mixed gas generator, liquid or semi-liquid fuel rich in hydrogen, such as fuel oil, crude petroleum and the like may be introduced into the retort. With an intermittent mixed gas generator of the kind in question there may advantageously be used valve apparatus of the kind described in the specification of British Patent No. 112091, and the admission of steam to the generator and the opera tion of the said valve apparatus may advantageously be effected and 'controlled by apparatus of the kind described in the speci- Hcation of British Patent No` 159409.

`Whilst in the manufacture of gas for heating or illuminating purposes it is not desirable to crack or split up such substances as methane, in the case of the present invention it is desirable that all hydrocarbons should be split up into hydrogen and carbon, the latter being available for the reaction with steam to form water-gas. ln order to insure this complete or'substantially complete crackingof the volatile hydrocarbons present in the products of distillation of the coal in the retort, it is important that the fuel in the lower fuel chamber, and the cheq* ucr-Work in the jacket of theretort, should be maintained at such a high temperature that the Water gas reaction within the lower fuel chamber cannot be carried ont mainly according. to the equation C-i-2H2O:

comparatively low temperature. lft is therefore preferred to carry out the water gas reaction within the lower fuel chamber priucipally according to the equation C14-H2O: VOA-H2, although the reaction to carbon dioxide may be used as far as is compatible with the maintenance of a sufficiently high temperature to insure the cracking and gasification of substantially the whole of the volatile hydrocarbons evolved from the coal. By working the generator in this way the make gases will lea-ve it at a high temperature, say 1000o C. to 11000' C.: so that. after mixing with steam, the gas and steam mixture can be obtained at a suitable temperature for treatment in the converter as described below.

In order to effect the conversion of the carbon monoxide` the gases issuing from the intermittent mixed gas generator during the make period are passed into the carbon monoxide converter K wherein they are subjected at a comparatively low temperature to the action of additional steaml in such manner that a considerable proportion of the carbon monoxide in the gas will be converted into carbon dioxide with the production of further hydro en according to the equation Cod-H20: Ofi-H2. Since this reaction is exothermic little or no heat need be supplied to the converter except to compensate for radiation losses. The converter K may be filled with chequer-work or with pieces of refractory material presenting a large surface for promoting catalytically the desired reaction, or preferably it may contain suitable catalyst material supported for instance on perforated trays superimposed one above the other. In certain cases part of the converter vessel may contain chequer-work and another part trays o f catalyst material or two converter vessels may be used one of which may contain chequer-work and another trays of catalyst material. At the commencement of operations in order to raise the converter to the desired high temperature, gas from the generator or from another source may be burnt therein, the said gas passing around the retorts in the converter containing the catalyst material. When the desired temperature of the converter has been reached, the supply of heating gas is cut off, blow gases admitted through the pipe'V being substituted. The converter is so constructed that the blow gases passed therethrough and the products of combustion of the gas used for heating it up as described above, in order to avoid any detrimental effect on the catalyst material do not come into direct contact therewith. After passing through the converter the blow gases escape by the pipe W. Should the heat of the blow gases be insuliicient to maintain the desired temperature in the converter, a small quantity of air may be blown into the top part of the converter and there be burnt with a portion of thev hydrogen and carbon monoxide of the gas under treatment. ln working the carbon monoxide converter it is preferred to pass the gas and steam into it in a downward direction and to add a portion only of the total steam required at the top of the apparatus.` The temperature of the steam used should be such that the temperature of the mixture of gas and steam at the top of the apparatus should be between about 600o C. and 800o C. and preferably about 700C C. The mixed gases from the generator produced during the make enter the top of the converter through the pipe U, passing in the direction R, S, T, U, or J, J', J, T, U, according as the steaming is taking place in the upward or downward-direction, and after passing, together with the additional steam admitted, over the catalyst material finally leave the converter by the pipe Y` hence passing through the ,washbox X and to scrubbers and gas holders whereupon they may be treated as subsequently described. As indicated in Figure 1, part of the total additional steam required for effecting the react-ion in the converter is admitted atthe top of the apparatus through the pipes Z, while the remainder of the steam is preferably introduced at several points on the way down the converter (as for example through the pipes Z and 2) so as not only to neutralize the rise in temperature due to the heat of the reaction but to produce a gradual decline in temperature from the to of the converter to the bottom thereof w ere the temperature should be between 400 C. and 550 C. and preferably may be at about 100o C. The precise temperatures to be employed depend upon the particular catalyst which is used. The degree to which the reaction should be carried in the carbon monoxide converter, subject of course to the limit which is practically obtain able, may be varied to suit circumstances, particularly1 with regard to the arrangements to be used for raising and superheating the steam` and it may be, the purposes for which the resulting gas is to be used. v

The treated gas leaving the carbon monoxide converter is passed through a condenser to remove the excess steam or it may be passed through a boiler, heat interchanger, or the like, in order to utilize the latent heat of excess steam and also the sensible heat of the gases. The cooled gas, which will now consist almost entirely of hydrogen and carbon dioxide together with comparatively quite small quantities of carbon monoxide and nitrogen, is subse uently treated in a known and suitable way or the separation, as far as possible or desirable of the hydrogen from the other constituents of the gas.

To remove the carbon dioxide the gas Leraar-e may conveniently be washed in an absorp- .tion tower or towers with water, preferably under pressure and with or without the addition of lime water, ammonia, or the like, in order to remove the last portions of carbon dioxide, the How of water or solution being counter-current to that of the gas. lifter this treatment, the gas, if necessary, can be further treated for the separation of the hydrogen therein from -the other constituents present, as for instance by liquefaction, When carrying out the conversion process so that very little carbon remains in the gas leaving the converter, separation of the hydrogen from the other constituents of the gas by liquefaction may be unnecessary and might for instance be replaced, so far as removal of carbon monoxide is concerned, by the known method of causing the latter to react with hydrogen in presence of a catalyst producing methane and waten From the foregoing description, it will be seen that the apparatus used in carrying out the invention comprises essentially an intermittent mixed gas generator operatively eombined with a carbon monoxide converter and may conveniently be followed by an absorption apparatus, for the removal of carbon dioxide, these being in communication with each other and acting in conjunction with each other.

lln carrying out the present invention the uel used is coal or other bituminous fuel 5 containing as high a percentage of hydrogen as possible and as before mentioned the hydrocarbons obtained by gasication of the coal are cracked or split up, as com pletely as possible, into hydrogen and carbon, which latter is available for the water gas reaction as well as the so-called fixed carbon of the coal, so that the products of the process consist practically entirely ofnon-condensable gases and ashes, whilst the carbon monoxide produced in the first stages of the process is converted to a large extent by steam into carbon-dioxide, setting free the hydrogen in this steam, and thus producing as a linal result substantially more hydrogen per ton of coal than is obtained by any of the processes hitherto known.

at we claim and desire to secure by Letters Patent of the United States is 1,. A process for the production of hydrogen or gases rich in hydrogen which consists in completely gasifying coal in an intermittent mixed gas generator, taking od from the generator the hot mixture of gases resulting from the complete gasification, the said gases consisting largely of hydrogen and carbon monoxide with some carbon dioxide, subjecting the said mixture of gases while still in the heated condition and without any intermediate cooling to treatment with steam in the presence of a catalyst in a carbon monoxide converter and maintainh ing a gradual fall of temperature between the two ends of the said converter' by introducing a portion of the required amount of steam at or near that end oi the converter at which the hot mixture oi' gases .from the generator is admitted and the remainder of the steam required at a plurality of points between the two ends of the converter.

2. A process for the production oihydrogen or gases rich in hydrogen which consists in completely gasiliying coal in an intermittent mixed gas generator, taking onf from the generator the hot mixture of gases resulting from the complete gasification, the said gases consisting largely or' hydrogen and carbon monoxide with some carbon dioxide, subjecting the said mixture of gases while still in the heated condition and without any intermediate cooling to treatment with steam in the presence oi' a catalyst in a carbon monoxide converter and maintaining a gradual fall of temperature between the two ends of the said converter by introducing a portion of the required amount of steam ator near that end of the converter at which the hot mixture of gases from the generator is admitted and the remainder of the steam required at a plurality of points between the two ends ci the converter, and effecting the operation of the intermittent mixed gas generator in such manner that the mixture of gases consisting largely of hydrogen and carbon monoxide with some carbon dioxide leaving the generator is at a temperature substantially high enough to insure that, after the ad dition of steam thereto, the resulting gas steam mixture will be at thefdesired temperature for treatment in the converter.

3. A process for the production of hydrogen or gases rich in hydrogen which consists in completely gasifying coal in an intermittent mixed gas generator, taking oil from the generator the hot mixture of gases resulting from the complete gasification, the said gases consisting largely of hydrogen and carbon monoxide with some carbon dioxide, subjecting the said mixture of gases while still in the heated cpndition and without any intermediate cooling to treatment with steam in the presence of a catalyst in a carbon monoxide converter sol as to effect replacement of the carbon monoxide in the gases by carbon dioxide and hydrogen, passing hot blow gases from the intermittent mixed gas generator through the said converter but in indirect contact with the catalyst material therein so as to maintain the carbon monoxide converter at the desired temperature for the reaction of the mixed gases with steam, and maintaining a gradual fall of temperature between the two ends of the said converter by introducing .a portion of the required amount of steam at or near that end of the converter at which the hot mixture of gases from the generator is admitted and the remainder ofv the steam required at a plurality of points between the two ends of the converter.

4. A process for the production or' hydrogen or gases rich in hydrogen which con sists in completely gasifying coal in an in# termittent mixed gas generator, taking oli" from the generator the hot mixture of gases resulting from the complete gasification, the said gases consisting largely of hydrogen and carbon monoxide with some carbon dioxide, subjecting the said mixture of gases while still in the heated condition and without any intermediate cooling to treatment with steam in the presence of a catalyst in a carbon monoxide converter so as to effect replacement of the carbon monoxide in the gases by carbon dioxide and hydrogen, and maintaining the temperature of the gases at that end at which the gases enter the carbon monoxide converter at about 600 C. to 800 C. and the temperature of the gases at that end at which the gases leave the converter at about 400 C. to 550 C.

5. A process for the production of hydrogen or gases rich in hydrogen which consists in completely gasifying coal ain an in termittent mixed gas generator, taking oli from the generator the hot mixture of gases resulting from the complete gasification, the said gases consisting largely of hydrogen and carbon monoxide with' some carbon dioxide, subjecting the said mixture of gases while still in the heated condition and without any intermediate cooling to treatment with steam in thepresence of a catalyst in a carbon monoxide converter so as to eli'ect replacement of the carbon monoxide in the gases by carbon dioxide and hydrogen, maintaining the carbon monoxide converter at the desired temperature for the reaction 'of the mixed gases with steam by passing hot blow gases from the intermittent mixed gas generator through the said converter but in indirect contact with `the catalyst material therein, and maintaining a gradual fall of temperature between the two ends of the said converter by introducing a portion of the required amount of steam at or near that end of the converter at which the hot mixture of gases from the generator is admitted and the remainder of the steam required at a plurality of points between the two ends of the converter, the temperature of the gases at the hotter end of the carbon monoxide converter being maintained at about 600 C. to 800o C. and the temperature of the gases at the cooler end of the converter being maintained at about 400 C. to 550 C.

JOHN HENRY WEST. ARTHUR J AQUES. CORNELIUS BRITTIFFE TULLY. 

